1. Cyst forms found in the feces .......... Go to: 3 & 4
2. Trophs (active forms) found in diarrhetic stool, intestinal scrapings, or mucosal impressions ........ Go to: 10, 11, & 12

3 Cysts (small oval or large round) without distinct refractile cyst wall. But does contain distinct cellular organelles. Usually seen during a direct (saline) fecal exam. .......... Go to: 5 & 6
4. Cysts (medium, small or very small) with distinct refractile cyst wall, may be unsporulated or sporulated. But does not contain distinct cellular organelles. Usually seen during a (simple or saturated sugar) floatation .......... Go to: 7, 8, & 9

5. Large round cyst easily seen with a 10X objective, large dark nuclei may be noted within the cyst .......... Balantidium coli
6. Small oval cyst containing 4 round nuclei at one end and dark lines (axostyle & median bodies) extending through the cyst. .......... Giardia sp.

7. Round to oval medium-sized cysts (oocyst), may be flat on one end. Seen during fecal floatation. Unsporulated: oocyst contains a single cell. Sporulated (Cultured): oocyst contains 2 sporocysts .......... Isospora sp.
8. Small oval cysts (naked sporocysts) that contain 4 sporozoites, and many round refractile inclusions (sporocyst residium). .......... Sarcocystis sp.
9. Very small cysts that require acid-fast staining to verify identification .......... Cryptosporidium sp.

10. A large oval ciliate easily seen with a 10X objective, (usually swimming rapidly) .......... Balantidium coli
11. A small tear-shaped or pear-shaped flagellate with 2 nuclei and an dark line (axostyle). (The organism slowly "wobbles" around the slide) .......... Giardia sp.
12. A small amoeba (variable shape) with 1 round "bull's-eye" nuclei and may contain vacuoles with host RBC's .......... Entamoeba histolytica